Japanese non-examined laid-open Patent Publication No. 2004-255542 discloses an electric hammer which performs a hammering operation by driving a hammer bit. The electric hammer has a motor and a piston, and rotation of the motor is converted into a linear reciprocating motion of the piston. By utilizing the linear motion of the piston, the hammer bit held by a tool holder is hit by a hammering element within the piston via an intermediate element and thereby the hammering operation is performed.